Integer overflow in Nmap
CVE-2026-58058
Nmap through 7.99 does not keep the IPv6 extension-header walk within the captured packet in ipv6_get_data_primitive (libnetutil/netutil.cc), so the pointer advances past the buffer and the remaining-length computation underflows to a large value. A scanned target or on-path attacker returning a crafted IPv6 response with a truncated extension header can trigger out-of-bounds reads and a crash during raw IPv6 scans.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L.
EPSS exploit prediction
EPSS: 0.015 (72.6th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 73rd percentile — 72.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.014 · newest: 0.015 · change: +0.001
Affected products
- Nmap — versions 0
Weakness classification (CWE)
References
- github.com/bikini/exploitarium/tree/main/nmap-ipv6-extlen-wrap-poc (exploit, Broken Link, third-party-advisory)
- github.com/nmap/nmap/commit/bb6754e76bb1686315008e1aa1c40202a513fb83 (Patch, patch)
- nmap.org/changelog.html (release-notes, Patch, Release Notes)
- www.vulncheck.com/advisories/nmap-integer-underflow-in-ipv6-extension-header-pa… (Patch, Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-58058?
- CVE-2026-58058 is a medium-severity vulnerability in Nmap, classified under Integer Underflow. CVSS score: 6.5/10. Published 2026-06-28.
- How severe is CVE-2026-58058?
- Medium severity. CVSS v3 base score is 6.5 out of 10.